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Topics in Antiviral Medicine ; 30(1 SUPPL):103, 2022.
Article in English | EMBASE | ID: covidwho-1880096


Background: Understanding the long-term kinetics of the immune response against SARS-CoV-2 infection is crucial in guiding public health policies and optimizing of vaccination strategies. While it is known that SARS-CoV-2 specific antibodies may persist in adults 12 months after infection, data are lacking in the pediatric population. We herein describe the long-term immune response in children following SARS-CoV-2 infection. Methods: Single-centre, prospective observational study analyzing family clusters of COVID-19 attending the Pediatric Department, University of Padua (Italy). Confirmed COVID-19 infection was defined by positive SARS-CoV-2 PCR and/or IgG serology. All patients with confirmed infection at enrolment underwent serological follow-up at 1-4, 5-10, and >10 months after infection. Plasma was analyzed to quantify anti-SARS-CoV-2 S-RBD IgG, by chemiluminescent immunoassay, performed on MAGLUMI™2000 Plus (Snibe Diagnostics). IgG title >4.3 kBAU/L was considered positive. Results: Among 902 subjects (252 COVID-19 family clusters), 698 had confirmed COVID-19, including 352 children/older siblings aged 8.6 ±5.1 years, and 346 parents aged 42.5 ±7.1 years;of those, 96.5% cases had asymptomatic/mild COVID-19. Children showed significantly higher S-RBD IgG titers than older subjects across all follow-up time points, with an overall mean S-RBD IgG titer <3 years of age five-fold higher than adults (282.3 [139-516.6] kBAU/L vs 56.7 [24.6-136.9] kBAU/L, p<0.001) (Table). The longitudinal analysis of 60 subjects sampled at least twice during follow-up demonstrated the persistence of antibodies up to 10 months from infection in all age classes. Subjects >6 years of age showed a significant progressive decline of the S-RBD IgG titer from the first serological follow-up. While, in younger children antibodies remained stable at 5-10 months of follow-up (p=0.0625), with a subsequent significant decline afterwards (p<0.001). Conclusion: In our unique family cluster cohort, we confirmed the different kinetics of the COVID-19 humoral response across several age groups of asymptomatic/mild COVID-19 cases in our family-cluster cohort. Children presented with higher S-RBD IgG titer at every time point up to 10 months of follow-up. Children less than 3 years demonstrated a more intense long-term resilience of their immune response, which started to decline significantly only after ten months from infection.

Topics in Antiviral Medicine ; 29(1):240-241, 2021.
Article in English | EMBASE | ID: covidwho-1250171


Background: Recent evidences suggest that SARS-CoV-2 neutralizing antibodies (Nabs) may persist over time, however lack of knowledge still regards the pediatric population. Methods: A single-centre, prospective observational study evaluated family clusters of COVID-19 attending the Pediatric Department, University Hospital of Padua (Italy). Confirmed COVID-19 was defined by positive SARS-CoV-2 molecular detection and/or serology;patients/family symptom's and virological positivity were considered to define the infection onset (baseline). Blood samples were analyzed in pair to detect Nabs through Plaque Reduction Neutralization Test (PRNT), and IgG through chemiluminescent immuneenzymatic assay (CLIA) MAGLUMI™ 2000 Plus;IgG >1.1 kAU/L and/or PRNT≥1:10 were considered positive. SARS-CoV-2 viral load (VL) was quantified by multiplex quantitative assay based on One-Step RT-ddPCR. Geometric mean titers (GMT) and 95% Confidence Intervals of IgG/PRNT were evaluated, stratified by age and time from baseline to sample collection. Trends over time of immune-virological response were assessed. P-value <0.05 was considered statistically significant. Results: Among 213 subjects (57 families) evaluated, 155 had confirmed COVID-19 including 73 (47%) children/older siblings of 8 years median age (IQR 4-13) and 82 (53%) parents aged 42 years (IQR 34-46);93.5% had asymptomatic/mild COVID-19. From the cumulative analysis of 194 blood samples, Nabs persisted over a median period of 95 days (IQR, 67-133) from baseline. Children showed significantly higher NAbs than older subjects, with children <3 years ranging from a 4-fold difference at 1-2 months to 8.8-fold difference at 3-6 months after baseline, compared to adults (table). The longitudinal assessment of 42 subjects sampled at 60 days (SD+/-9.9) and at 150 days (SD+/-24.2) showed a 2-fold increase in NAbs in children <6 years (PRNT 144, 95% C.I. 74.42-277.94 versus 303, 95% C.I. 196.43-468.57) and a substantial stability in Nabs among older subjects. CLIA IgG significantly decreased over time for all age classes, becoming negative in 13/42 subjects (31%), compared to 1/42 subjects detected by PRNT. Among 32 individuals checked for VL within 4 days from baseline, VL directly correlated with PRNT titers in subjects >15 years (Pearson Coefficient =0.70, p=0,0349) but not in pediatric cases. Conclusion: Asymptomatic/mild COVID-19 disease triggers in children a superior and persistent humoral response compared to adults.

European Heart Journal Cardiovascular Imaging ; 22(SUPPL 1):i193, 2021.
Article in English | EMBASE | ID: covidwho-1185662


Background: Evidence suggests that clinical manifestations of children's COVID-19 may be less severe. However, it has been described the pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) which resembles other inflammatory conditions (i.e. Kawasaki disease). Patients affected by PIMS-TS showed cardiac involvement with myocardial injury, reduced left ventricle systolic function and coronary artery abnormalities. Little is known regarding cardiac involvement in pediatric patients with asymptomatic or mildly symptomatic SARS-CoV-2 infection. Methods: We analyzed 23 pediatric patients (13males, 56%) with diagnosis of SARS-CoV-2 infection based on PCR analysis of nasopharin-geal swab (NPS), and asymptomatic or only mildly symptomatic for COVID-19. Patients underwent standard transthoracic echocardiogram (TTE) within 2-3 month from diagnosis and after negative NPS for SARS-CoV-2. We performed offline analysis with GE EchoPAC software to measure global longitudinal strain (GLS) of the LV using 2D speckle tracking imaging. Therefore, we compared the results with a matched group of 23 controls (13males, 56%). Results: Cases and controls were similar regarding age (5.9 ± 4.1years vs. 6.4 ± 4.4 years, p = 0.63), body surface area (0.98 ± 0.3m2 vs. 0.8 ± 0.4m2, p = 0.17), LV FS (37.9 ± 5.9% vs. 36.4 ± 8.3%, p = 0.74) and LV biplane EF (63.9 ± 5.2% vs. 66.4 ± 5.3%, p = 0.11). GLS analysis showed significant strain reduction of the LV mid-wall segments and of the basal anterior, posterior and septal inferior segments among cases compared to controls. Furthermore, in the case group there were 7 subjects (30%) with a strain below 16.5% in at least 3 segments. Conclusion: SARS-CoV-2 infection may affect LV deformation in asymptomatic or only mildly symptomatic children, showing a peculiar pattern with lower longitudinal strain in all mid-wall segments of LV compared to control subjects. The clinical significance of this findings is unclear and follow-up is needed to verify the reversibility of this alterations.